forum.polymake.org

Dear all,

I am using topaz to read faces of a simplicial complex and print facets. I find that the vertex indices that are input using INPUT_FACES get re-ordered to start from 0 compactly, so when I print FACETS I get different labels and have to match it up. E.g if my input faces are

topaz > print $sc->INPUT_FACES;
{5 6 8}
{6 8}

and my FACETs are

topaz > print $sc->FACETS;
{0 1 2}

What I want to get is {5 6 8}, ie, preserve the labels, or map it back into what was input. My input faces need not be maximal.

Is there a simple way? I see VERTEX_LABELS and VERTEX_INDICES and can do the mapping offline with some work but I was wondering if polymake has a way to do this automatically. This must be a commonly encountered need, so how do people get around it?

Sorry if it is a naive question, I am a newbie here.

thanks!

-Ram

does almost exactly what you want. Each row is decorated with a sequential number, but this should not disturb you.

What about the following? The second parameter "undef" can be replaced by something meaningful if you also want to give names to the facets.

Perfect! Just what I need!

Thanks very much for the quick responses.

-Ram